This proposal is an application for funds to add special hardware and software to an existing whole body magnetic resonance imaging system that is dedicated to research studies only in order to permit ultra fast echo planar imaging (EPI) acquisitions in times substantially less than one second. This hardware comprises a replacement, high strength gradient coil and associated gradient amplifiers that can be very rapidly switched to produce multiple gradient echoes in a short time' There is also a dedicated computer and data acquisition system to permit multiple serial fast images to be acquired, stored, and displayed. The EPI capability will be important in several areas of application of MR imaging and is considered essential for progress in new directions in several funded projects. In particular, the ability of EPI to detect regional brain activation because of the accompanying alterations in blood oxygenation that in turn change the magnetic homogeneity of tissue, in response to specific appropriate stimuli, will likely produce important advances in our understanding of brain function and assist the diagnosis of different brain disorders. The application highlights funded research applications for functional brain imaging in the study of working memory and schizophrenia, for the depiction of specific areas involved in semantic processing in dyslexia, for localizing epileptic foci in refractory disease, for localization of motor and sensory areas, and for speech and, language areas. Functional brain imaging will form an essential component of major research programs in each of these areas. The stronger gradients will also permit artifact free diffusion weighted imaging to be performed in humans, which has important potential for the study of acute stroke and other conditions. The faster time resolution will also offer unique abilities for imaging the heart, and in our proposed studies these will be used for providing data for better quantifying regional myocardial wall motions in canines. These applications of the new facility will be supplemented by studies using the equipment designed to better understand the origins of contrast in diffusion weighted and susceptibility contrast imaging. All these projects will benefit considerably from the EPI upgrade and the combined effect of this work is likely to accelerate the introduction of fast imaging into clinical practice as well as basic research.